Tour de France 2015: Five things we have learned

(CNN)Chris Froome became a double Tour de France champion Sunday and even his fiercest critics would concede it was a deserved victory for the British cyclist.

After taking a commanding lead in the Pyrenees, Froome had to defend himself against thinly veiled allegations of doping, sparking unpleasant spectator reaction.
Froome was subjected to abuse, had a cup of urine thrown over him and was spat at by errant spectators.
All this as well as having to fight off Nairo Quintana's late challenge on the legendary Alpe d'Huez on the penultimate day of the race.
    Froome also did the rare double of yellow and polka dot jerseys, the latter for points gained on the mountain climbs, the key to his victory.
    It all added up to an intriguing Tour, with a series of lessons to be learned for both organizers and riders.

    1) Doping remains a thorn in the side of the Tour

    Aside from Italian veteran Luca Paolini being sent home in disgrace for testing positive for cocaine after stage four, it has been, at least testing wise, a clean Tour.
    But after Froome trounced the opposition on the first mountain stage in such convincing style, previously confidential data on his performance found its way into the public domain and host broadcaster French 2 chose to reach its own conclusions.
    It enraged Froome, who has never failed a doping control, though earlier this year he did admit to missing one test in 2010 and one in 2014. The current rules state that three in a 12-month period leads to a suspension.
    Froome pointedly referenced the show's presenters, former stars Laurent Jalabert and Cedric Vasseur, who rode during the Lance Armstrong era when doping appeared widespread in the professional ranks.
    Vasseur was, however, cleared of doping in an investigation into his team Cofidis in 2004, though In 2013, French newspaper L'Equipe said a 1998 Tour de France sample from Jalabert, which was re-tested in 2004, showed traces of the blood-booster EPO.
    "I cannot say for sure say that I have never taken anything banned," Jalabert told a French Senate investigation committeein May 2014, reported Reuters.
    "I have effectively used products when necessary, in case of lesions or other injuries. At ONCE, in the evening after the stages, the doctor took care of us for our recovery, but we didn't really know what it was.
    "A relationship with doctors based on mutual trust was established, so we did not ask any questions. We were treated, I have never said otherwise. Were we doped? I believe we were not."
    The appearance of disgraced seven-time winner Armstrong to ride two stages of the Tour for charity was hardly helpful in this context and Froome and Team Sky spent the rest of the Tour protesting innocence.
    It also appeared to inflame a minority of the home fans who lined the route and Froome and his teammates all reported uncomfortable incidents.
    Team Sky published Froome's power data, while the team's boss Dave Brailsford said the Kenyan-born Briton had shown "real mettle."

    2) The Tour is growing in popularity

    While others sports may have wilted in popularity with such adverse publicity, the opposite appears the case with cycling and in particularly its jewel in the crown, the Tour de France.
    The roadsides were packed and such was the clamor to see the top riders at close hand on the Alpe d'Huez, organizers had to shut it off for fully a week ahead of the 20th stage.
    A montage of photographs showing fan fervor on the 20th stage of the Tour de France on the Alpe d'Huez.
    An estimated million fans watched the epic showdown between Froome and Quintana and the enthusiasm for the Grand Boucle is not purely confined to countries with a cycling tradition.
    Sports market intelligence experts Repucom say interest in Italy has grown to 30% of the population, joining France (32%), The Netherlands (33%) and Spain (38%) as the biggest markets.
    But even in the UAE, where there is no history of professional cycling, there has been a 12% increase in interest among the public.
    This is reflected in sponsorship deals where for the first time in Tour history, five brands are included in the highest tier.
    "The rise in fan interest internationally, especially in markets such as the UAE, provides some crucial clues as to potential future investors into the Tour and the sport more generally," said Repucom's Mike Wragg.

    3) The wait for a home winner could be a long one

    Admittedly, Thibaut Pinot covered himself in glory with an epic Alpe d'Huez victory, but after last year's third place for the FDJ rider he was never a factor in the hunt for yellow.
    Pinot was hit by mechanical issues on the cobbled third stage and then compounded his problems by clumsily falling off on a downhill section when looking set for a later stage win.
    Saturday provided part redemption but he was only allowed free rein by the big guns because he was so far down the overall classification.
    Romain Bardet also won a stage and was the best of the French in ninth spot overall, 16 minutes behind Froome. Pierre Rolland was next in 10th, while the much-touted Warren Barguil took 14th.
    Barguil will also be remembered for a misjudgment on a downhill section in the final week which saw him barge into Britain's Geraint Thomas and send the Team Sky rider careering into a telegraph pole.
    Fortunately, Thomas was not seriously injured, but he slipped down in the overall classification after the incident.
    With Froome, last year's winner Vincenzo Nibali and Giro d'Italia champion Alberto Contador still a force, it is difficult to see who will snap the French victory drought dating back to Bernard Hinault in 1985.

    4) The Africans are coming

    African success in long distance running has led many experts to predict they could eventually be a major factor in the ultimate endurance tests in cycling such as the Tour de France.
    2015 may well be the year that that theory gained more credence as Daniel Teklehaimanot, from Eritrea, made history by becoming the first African to wear the polka-dot jersey.
    He also rode a bold attacking race with promise of greater things to come.
    There was also the first win for African-based team MTN-Quebeka, when Britain's Steve Cummings took the 14th stage, fittingly on Mandela Day -- the anniversary of the former South African president's birthday.
    Remember too, Froome was born in Kenya, but chose to pursue his professional career representing Britain, birthplace of both his parents.

    5) Doubling up so hard to do

    Contador went into the 102nd edition of the Tour looking to add to his Giro d'Italia triumph and to complete the full set of Grand Tours within a calendar year, having won the Tour of Spain in September 2014.
    Contador was backed by a strong Tinkoff-Saxo team but it was clear from the initial skirmishes that he lacked the form required to challenge the likes of Froome and Quintana.
    His dream effectively died on the stage from Tarbes to La Pierre-Saint-Martin where Froome made his decisive move and opened up massive time gaps.
    Contador eventually finished fifth, not the place he was thinking of when talking up his chances of the Giro-Tour double.
    The Spaniard does not regret his decision to attempt to become the first rider since Marco Pantani in 1998 to achieve the feat.
    "If I hadn't tried, then after my career I might have wondered whether I could have done the Giro-Tour double, and now I know," he said.
    Another rider looking to double up, in this case to defend his 2014 title was Vincenzo Nibali, but like Contador, the Italian wilted in the Pyrenees and had to settle for fourth.